Electric circuit interrupter



Jul 22,' 194L s. R; SMITH, JR

ELECTRIC CIRCUIT I-NTERRUPTER Filed July 19, 1939 Figh 39 Insulator a TM Ihventor: Sidney R. SmitmJn,

Att orn ey.

Patented July 1941 ELECTRIC CIRCUIT INTERRUPTER Sidney a. Smith, Jr., Pittsfleld, Mass., asior to General Electric,Company, a corporation ot New York Application July 19, 1939, No. 285.340

' BClaims.

The present invention relates to electric cir-' cuit interrupting devices, and has !or an object the provision of .an improved, simplified, and low cost indicating circuit interrupter which requires no separate insulating support and which is suitable for suspension mounting directly on a line conductor or conductors oi' an overhead electric line.

A further object of the invention is the provision of an improved form of line suspension in-' dicating 'secondary" ruse cutout.

The invention has also, as one of its specific objects, the provision oi' a circuit interrupting unit which is suitable for suspension mounting directly on the conductors of an electric line. and which has improved 'supporting means operative'normally to impose tension on the conductor of the unit and operative in response to circuit interruption to eflect movement of an element or elements of the unit to indicating position.

As a further object o! the present invention, I contemplate the provision of simple and low cost apparatus for carrying out certain aspects of the invention set forth and more broadly claimed in my application, Serial No. 285,339,-

filed concurrently with the presentapplication and assigned to the same assig nee as the present invention.

Otherobjects and the details of that which I consider to be novel and my present invention will become apparent i'rom the following description and the claims appended'thereto, taken in conjunction with the accompanying drawing wherein are shown two exemplary embodiments or the invention. In the drawing, Fig. 1 is a side elevation. partially cut away, of one of the embodiments; Fig. 2 is a sectional elevation, partially cut away 'oi' the other of the exemplary embodiments; and Figs; 3 and 4 show the operated positions of certain of the parts of' the devices or Figs. 1 and 2 respectively. V

Thecircuit interrupting unit o! Fig. 1 has an insulating fuse holder or carrier which comprises,

in the main, an insulating tubular casing o,

a concentricall disposed inner tube H oi' insulation, and insuiating end plates I2, one of which end plates is shown in the drawing. The space between the inner and outer tubes provides an expansion chamber |3 which is in communication, by means of holes Il, with the arcing chamber IS formed by inner tube ll. Two metallic straps s are clamped around the insulating carrier, respectively adjacent opposite ends thereoi', and are fixedly secured to the carrier the carrier in parallel spacd apart relation-` ship, and have a pivot pin 22 extending therebetween. ,Fulcrumed respectively on the pins 22 are two metallic bell-crank levers 23 which are arranged for swinging in opposite directions relative to each other and the body of the carrier.

One arm, 24, of ea'ch of the levers 23 normally extends transversely of a respective one of the ends of the insulating carrier, and is provided with a fianged cap 25 designed to cover the corresponding end of the carrier. Each of the caps 25 includes a longitudinaily bored terminal element 26. Normaily levers 23 are restrained in fixed relation to the body of the carrier, in the positions shown in Fig. 1, by the strain member of a fuse link connected between arms 24 of thelevers and extending through inner tube H of the carrier. In the drawing there is shown, by way of example, a simple form of fuse link hav- `ing a fusible section, comprised of a ruse wire tial angle, which is approxmately degrees in the exemplary embodiment illustrated, to the arms 24 of the levers. provided, adjacent its outer end, with an elongated siot 33 for accommodation of a bolt 34 which serves pivotally to join the corresponding lever 23 with a conductive supporting hanger 35. Resilient washers 36 preferably are provided for mainta'ning good electrically conductive contact between the levers and the supporting hangers.

The hereinbefore described crcuit interrupting unit is designed for suspension mounting didectly on, and to electricaily interconnect, two electric line conductors, such as 31 and 38, which are mechancaily joined but electrically insulated from each other by a common form of strain insulator such as indicated at 39. For attachment of the circuit interrupting unit to the line conductors, each of the supporting hangers'35 is provided with suitable conductor clamping Each of the arms 32 is I :i'mus. By way of example, there is illustrated a simple .form of clamping means which compriscs a clamping plate relatively loosely supported on the hanger strap 35 by means of bentover lugs 4! which form part of plate 40, and a clamping bolt 42 which is provided with a cooperating Wlng nut 43. With clamping plate i& loose, the hanger may a line conductor, and then the conductor is ciaznpccl between the hanger strap and the clamping plate by tightening up on wing nut 83. The clamping plate has an overhanging portion 44 arranged to rest on a supporting line conductor in the manner shown so as to insure against disengagement of the hanger from the line conductor.

When the circuit interrupting device is mounted on and connected in an electric line as described, rupture oi the fusible section 21, 28, results in release of levers 23, which thereupon, due to the weight of the fuse carrier, pivot about both bolts B i and pins 22. Thus the arms 24 of the levers ure caused to swing outwardly in opposite directions from the ends of the use carrier to the positions illustrated in Fig. 3 to give an indication, clearly observable from a distance, of circuit interruption. The outward swinging of arms 24 with the terminals 26 carried thereby also effects a relatively rapid separation oi the ends of the ruptured iuse link and opens the ends of tube ll oi the carrier for expulsion of gases therefrom, all of which aids in extinction of the are and interruption of the current flow. Slots 33 permit the swinging of the levers relative to the fuse carrier even though the supporting hangers 35 are rigidly clamped to relatively taut line conductors so that the hangers themselves cannot swing appeciably.

In the construction of Fg. 2, the insulatin fuse holcler or carrier includes only a single, relatively long, insulating fuse tube having straps 5l elamped therearound respectively adjacent opposite ends of the tube and afiixed to the tube by self-threading screws 52 or other suitable means. In a manner similar to that prevously described 'in connection with the first embodiment, the upwardly projecting, spaced apart and substantially parallel ends 53 of the straps have pivot pins 54 extending therebetween, and on each of these pins is pivotally mounted a bell-crank lever 55 which serves as a terminal for the fuse holder or carrier. One arm 56 of each of the levers is provided with a fianged cap 51 for closing a corresponding one of the ends of tube 50. These caps normally are held in. closing relation to the ends of the tube by means of a fuse link connected and tensioned between the caps. It is preferable to provide the caps with some form of gasket 58 to seal the ends of the tube, thereby to insure against entrance of moisture into the tube to cause deterioration of the tube walls and the fuse link. Although any suitable form oi fuse link may be employed, there is illustrated a very simple form comprising a use wire 50, a strain wire BI, and terminal shanks 62, one of which terminal shanks may be seen in the drawing. These terminal shanks may be anchored to terminal caps 51 in any suitable manner as, for example, by passing the shanks through openings in the caps and soldering, as indicated at 63.

The other arms, 64, of the bell-crank levers project outwardly in opposite directions relative to each other and at a substantial angle to the arms 55, and each one of the arms 54 has one end of a flexible supporting conductor 85 fxedly be engaged readily with attached thereto in any suitable manner, as tor example, by crimping or welding. The other ends of conductors are provided with suitable clamping means for engagement with conductors, such as 31 and 38, of anelectric line, which conductors are mechanically joined but electrically insulated by means of a strain insulator 39. In the illustrated embodiment, there is employed a simple form of clamping means which includes a metallic yoke 66 and a clamping member 51 which is movable within the yoke by means of a clamping screw 88. One side of the yoke is partially open, as indicated at 69, to provide for engagement of the yoke with a line conductor. The yoke may be fastened securely to such line conductor by screwing the clamping member 61 upwardly so as to clamp the conductor between the clamping member and the overhanging end 10 oi the yoke. The end of the flexible supporting conductor 65 is embedded in or otherwise flxedly attached to clamping member 61 so as to insure a good electric connection.

The operation of the device of Fig. 2 upon rupture of the iusible section 60, Bl, due to overload or short-circuit, is similar to that prevously described in connection with the device of Fig. 1, in that the bell-crank levers 55 are released, and the fuse carrier drops down slightly so as to cause pivoting of the levers about points 54. The resultant outward swinging of caps 51, to their indicating positions illustrated in Fig. 4, opens the ends of tube 50 for expulsion of gases therefrom and also effects a relatively rapid separation of the ruptured fuse link ends to iacilitate arc extinction and current interruption.

As will be evident from the foregoing, the devices herein described are of simple construction. small, and easy to mount, and their insulating holders or carriers afiord good weather protection so as to insure against deterioration of the internal parts. Proper tensioning of the !use link, without excessive strain thereon, is provided by the described mounting arrangements. Also, the devices give a clear indication ot circuit interruption so that a lineman may readily determine from a distance when refusing is required. Replacement of blown fuse links with new ones may be accomplished easily upon removal of the interrupting devices from the supporting line conductors. However, devices such as those illustrated, and more particularly such as illustrated in Fig. 2; are of such simple and low cost construction that they may be discarded economically after operation and replaced by completely new factory assembled devices.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A circuit interrupting device comprising, current carrying means operable to interrupt an electric circuit, an insulating carrier thereior, an element pivoted on said carrier so as to be swingable relative to the body of the carrier, means restraining said element in a predetermined position relative to the carrier and arranged to release said element upon circuit interrupting operation of said first means, and two conductive supporting elements relatively permanently joined with said carrier and'electrlcally connected with said first means, each of which supporting elements has means adapted ior engagement directly with an electric line wire or the like for suspension mounting of said carrier, and one of said supporting elements comprising a conductor attached to said pivoted element at a point spaced from the pivot point ot the latter in a manner to impose on the pivoted element a` biasing force in opposition to said restrainlng means when said carrier is Suspended from electric line 'wires or predetermined position relative to the carrier and operative to release said element responsively to circuit interrupting operation, and two supporting conductors relatively permanently joined respeotively with said teminal means and each having means adapted for engagement directly with an electric line wire or the like for suspension mounting of said carrier, one oi' said supporting conductors being attached to said .pivoted element at a point spaced from the pivot point oi' the latter in a manner to impose on the pivoted element a -biasing force in opposition to the restraining force of said tensioned conductor when said carrier is Suspended fromelectric line wires or I the like by the supporting conductors.

3. A circuit interrupting device comprising an insulating carrier having spaced terminal means, at least one of which terminal means includes a bell-crank lever pivoted on said carrier so as to be swingable relative to the body of the carrier, circuit interruptng means including a tensioned conductor connected with one arm of said bellcrank lever so as normally to restrain the lever in a predetermined rier and arrang'ed to release the lever upon circuit interrupting operation, and two supporting conductors relatively permanently Joined respectively with said terminal means, one of said supporting conductors being Joined to the'other arm oi' said b'ell-crank lever and each ot the supporting conductors having means adapted tor engagement directly withan electrlc line wire :ir the like for suspension mounting of said car- 4. A circuit interrupting device comprising an insulating carrier having spaced terminal means comprising two lever-like' elements pivoted on said carrier so as to be swingable relative to each other and the body of the carrier, circuit interrupting means including a conductor tensioned between said elements so as normally to restrain the latter from swinging relative to the carrier and position relative to the car-` mally to restrain arranged to release said elements upon circuit interrupting operation, and two supporting conductors respectively Joined to said elements at points spaced from the pivot points of the latter, each of which means adapted for engagement directly with an electric line wire or the like for suspension mounting of said carrier.

5. A circuit interrupting device comprising an insulating carrier having spaced terminal means supporting 'conductors has comprising two bell-crank levers pivoted to Swing relative to each other and the body of the carrier, circuit interrupting means including a conductor tensioned between one arm of one of said levers and one arm of the other of the levers so -as normally to restrain the levers from Swingrelative to each other andvthe body of the carrier,

circuit interrupting means including a conductor tensioned between one arm of one of said levers and one arm of the other oi' the levers so as normally to restrain the levers from swingin relative to the carrier, said levers being releasable responslvely to circuit interrupting operation, and two supporting conductors each having one end 'pivotally attached to the other arm of a respective one of said levers, the free end of each of said supporting conductors having means adapted for engagement with an electric line wire or the like to support said carrier.

7. A circuit interrupting device comprising an insulating carrier having spaced terminal means comprising two bell-crank levers pivoted to Swing relative to ach other and the body of the carrier, circuit interrupting means including a conductor tensioned between one arm oi' one of the levers and one arm of the other oi the levers so as northe levers from swinging relative to the carrier, said levers being releasable responsivelyto circuit interrupting operation, and two flexible supporting conductors each having one end Joined to the other arm of a respective one of said levers, the free end of each of said supporting conductors having means adapted i'or engagement with an electric line wire or the like to'support said carrier.

8. A circuit interrupting device comprising an insulating housing deflning an arcing chamber having openings at opposite ends thereoi', two lever-like elements pivoted onthe housing to swingrelative to each other and the housing and each having a closure part, means to interrupt an' electric circuit in said chamber and including a conductor connected between said elements so as normally to restrain said closure parts in closing relation respectively to said openings, said conductor being arranged to release said elements responslvely to circuit interrupting emm R. SMI'I'H, Ju; 

